Plutonium is a man-made element, but minute quantities of it exist on earth. It's probable the earth had much larger quantities of it during its formation as a planet, but most of it decayed due to its half-life. In the same vein (no pun intended) as carbon-14 dating, is it possible to determine how much of it existed by determining if some of the radionuclides on earth are remaining products of its decay chain?
In other words, can we study uranium, lead, thallium, bismuth, etc. samples on earth and determine if they were transmuted from plutonium?